HEAT-PRODUCTION BY ADULT CRYPTOLESTES-FERRUGINEUS (STEPHENS) OF DIFFERENT AGES AND DENSITIES

The heat of respiration of adult Cryptolestes ferrugineus at three age s (one, four, and eight weeks old) at 2500 insects/200 g of wheat and three population densities (1250, 2500, and 5000 insects/200 g of whea t) with four-week old insects was measured in a computer-controlled, a diabatic respiratory calorimeter at three initial grain temperatures ( 15, 25, and 35 degrees C) and three moisture contents (MCs) [12, 15, a nd 18% wet basis (WB)]. Age, density, temperature, and MC significantl y affected heat production (P < 0.001). Heat production rates increase d with both increasing initial grain temperature and moisture content. Heat production by age was highest in four-week old adults (9.41 mu W /insect), whereas that of eight-week old adults (7.81 mu W/insect) was slightly higher than for adults one week old (7.40 mu W/insect). Heat production per insect by density was highest at 2500 insects/200 g of wheat (9.41 mu W/insect) and lowest at 5000 insects/200 g of wheat (6 .38 mu W/insect). Instantaneous rates of heat production measured over the test period were affected by the combination of age, density, moi sture content, and temperature increase.